The invention relates to an apparatus for controlling a torque transmitting system in a power train of a motor vehicle with a transmission and an engine, with an actuator controlled by a control unit for operating the torque transmitting system.
Apparatuses of this type are known in the art. Automobiles equipped with controlling devices of the aforementioned kind are controlled by the control unit during starting or acceleration phases using a method such that a starting phase takes place with a presentable engine torque and a presentable engine rotation (speed), whereby the torque transmitting system at a preset engine torque and a preset engine speed is intentionally engaged (closed) for accelerating the motor vehicle. Since it is not advantageous in all situations for the motor vehicle to start with the maximum acceleration, the engine torque is in general controlled to a value which is smaller than the maximum engine torque. If a partially loaded motor vehicle is accelerated, for example, from rest in, for example, level terrain using this apparatus and method, then this acceleration is usually sufficient. If, however, a significantly loaded motor vehicle is accelerated from rest on an incline, then this acceleration may be too small.
It is the object of the present invention to provide an apparatus of the aforedescribed type and a method which permit acceleration of a motor vehicle to be easily started up and accelerated from rest even if the motor vehicle is fully loaded and is positioned on an incline. It is another object of the invention to provide an apparatus and/or a method permitting an intentional controlled shifting of the accelerating or driving torque.
Further, the present invention provides an apparatus which constitutes an improvement over the conventional apparatus and which can be manufactured inexpensively and which is easy to use.
Even further, the present invention provides a control unit in at least one operating condition or state, such as starting or acceleration condition, which shifts between at least two operating states of the torque transmitting system with different transmittable torque, with the possibility to control a different, such as a higher or a lower, transmittable torque in the respective operating states, so that a different, such as a higher or a lower, torque is provided to power the motor vehicle. Thus, the invention provides an apparatus for controlling an actuatable torque transmitting system and a torque being transmitted at different rates by the torque transmitting system in a power train provided in a motor vehicle and further including an engine and a transmission arranged to drive the vehicle and to receive torque from the torque transmitting system. This apparatus includes a control unit and an actuator which is controllable by the control unit and which is arranged to actuate the torque transmitting system, such as a clutch, and wherein the control unit has at least one operating condition in which the actuator is arranged to effect a planned transmission of torque by the system at least at two different rates at each of which the transmission receives a different torque.
The engine electronics controls an engine torque and an engine rotation (speed) when the driver operates a load lever. Simultaneously, the torque transmitting system is controlled by the control unit in such a way that an intended torque can be transmitted. As a result of this control of the control unit and the engine, an equilibrium is established with respect to engine torque and engine RPM. Through the intentional shifting operation by way of a intentional control of the torque transmitting system, a different equilibrium state can be controlled at a higher engine RPM and a higher engine torque. This intentional shifting of the transmittable torque of the torque transmitting system consequently results in controlling the equilibrium state at different engine parameters leading to an intended increase/decrease of the accelerating engine torque.
According to the feature of the invention, it may be advantageous for the control unit to control intentional shifting between at least two operating states, such as starting and acceleration states. The two different operating states are characterized by different equilibrium conditions with respect to the engine torque and the engine RPM.
It is advantageous for the control unit to control shifting between at least two states depending on data sets, such as signals, quantities or other operating parameters, which are accumulated, determined and/or processed.
It is particularly advantageous in an apparatus of the invention if the control unit compares at least one data set with at least one presentable threshold value and controls shifting between two operating states, when at least one data set has at least reached, exceeded or lagged behind a threshold value. The at least one threshold value may be generated by the control unit depending on the operating point. The at least one threshold value may furthermore be determined from mapping, characteristic curves or by way of functional dependencies. The threshold values can be retrieved from or may be stored in memory.
It is also advantageous for the control unit to initiate a shifting operation between operating states when at least one data set which is detected or determined as a function of time, reaches, exceeds or fails to reach a presentable threshold value after a preset time.
In addition, it is advantageous if the control unit initiates a shifting operation between operating states when a sensor indicates that a load lever, such as a gas pedal, is operated in such a way that a preset threshold value for the load lever position has or has not been reached or exceeded.
Also, if the control unit initiates a shifting operation between operating states when during a first acceleration phase or starting phase of the motor vehicle a quantity representing the transmission input RPM, has not increased above a presentable threshold value after a preset time interval.
Further, it is advantageous if the control unit initiates a shifting operation from an operating state with a lower transmittable torque into a state with a higher transmittable torque in such a way that, during a first phase, there is effected an at least small decrease of the transmittable torque of the torque transmitting system, and that, during a second phase, the transmittable torque is increased to a higher target value.
Even further, it is advantageous if the control unit activates a shifting operation from an operating state with a higher transmittable torque into a state with a lower transmittable torque in such a way that, during a first phase, there is effected an at least small increase of the transmittable torque of the torque transmitting system, and that, during a second phase, the transmittable torque is decreased to a lower target value.
It is a particularly advantageous if the transmittable torque Mkset of the torque transmitting system which is controlled by the control unit, is a function of the engine RPM nmot: Mkset=k*f(nmot) wherein k is a proportionality factor which can also be varied. In this case, it is advantageous if the control unit determines the transmittable torque of the torque transmitting system, when there is a shift from one operating state into another operating state, according to the formula Mkset=k*f(nmot), wherein the control unit selects the value for k from within a range of values between 0 and a maximum value kmax and changes, for example increases or decreases, this value for k for a shifting operation.
In addition, it is advantageous according to the invention if during a intentional controlled switching operation from a first operating state into a second operating state with a higher transmittable torque, the control unit controls the torque at the driving end in such a way that the torque at the output end resulting from the transmittable engine torque is increased.
Moreover, it is advantageous in a method for controlling a torque transmitting system in the power train of a motor vehicle with a transmission, a torque transmitting system and an engine, with an apparatus for controlling a torque transmitting system, with at least one actuator controllable by a control unit, such as an actuating unit, for operating the torque transmitting system, wherein the control unit is in signal communication with sensors and possibly with other electronic units, that the control unit executes at least the following process steps:
a) recognizing an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal, b) recognizing an insufficient acceleration by resorting to at least one data set, such as a sensor signal, and c) initiating a different operating state with an increased driving torque.
Thus, a method is provided for controlling a torque transmitting system having different actuation states and being disposed in a power train of an accelerable motor vehicle, the method comprising the steps of: a) utilizing a control unit for monitoring the actuation states of the torque transmitting system based on at least one data set; b) utilizing the control unit for the detection of a potential insufficient acceleration of the motor vehicle based on at least one data set; and c) initiating an increased torque transmission in response to detection of insufficient acceleration.
It is also advantageous if the control unit executes at least the following method steps: a) recognizing an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal, b) recognizing an excessively high acceleration based on at least one data set, such as a sensor signal, and c) initiating a different operating state with an decreased driving torque. Thus, an other method is provided for controlling a torque transmitting system having different actuation states and being disposed in a power train of an acceleratable motor vehicle. Here, the method includes the steps of utilizing a control unit for monitoring the actuation states of the torque transmitting system based on a data set and utilizing the control unit for the detection of a potential excessive acceleration of a vehicle based on a data set; and initiating a decreased torque transmission in response to detection of excessive acceleration.
According to the invention, the control unit recognizes an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal, wherein a starting or acceleration state can be detected by way of at least one activated load lever, inactive brakes or a gear engaged in the transmission.
It is advantageous if the control unit accumulates or processes at least one quantity or a data set as a function of time and at least in general compares said at least one quantity to a presentable threshold value, wherein said quantity is a measure of the speed or acceleration of the vehicle.
The increase in torque available for accelerating the motor vehicle may be in the range of a few % to 50% of the nominal torque, depending on the engine torque for a normal starting phase and without shifting to a higher torque.
The increase in torque for accelerating the motor vehicle is achieved by controlling the torque transmitting system without changing the operation of the load lever. This is achieved in that the original equilibrium state with an engine torque and an engine RPM is set by a transmittable torque which is applied to the engine as load torque. If the transmittable torque is briefly reduced, then the engine RPM increases, resulting in a state with a higher engine torque. If the transmittable torque is subsequently increased, then an equilibrium state is reached again, with the resulting engine torque being larger than in the previous equilibrium state.
It is also advantageous to construct an apparatus for controlling a torque transmitting system and the torque transmittable by the torque transmitting system in the power train of a motor vehicle with a transmission and an engine with a load lever, with at least one actuator controllable by a control unit, such as an actuating unit, for operating the torque transmitting system, in such a way that the control unit, in at least one operating state, when the load lever is set to a load lever value, such as starting or acceleration state, if the acceleration of the vehicle is too small or too large, shifts between at least two operating states of the torque transmitting system having different transmittable torque by intentionally controlling the torque transmittable by the torque transmitting system, so that for a given load lever value a different, such as larger or smaller, available engine torque for powering the motor vehicle is generated. It is particularly advantageous, assuming that the load lever is operated in the same manner, if shifting to a larger or smaller available engine torque for accelerating or starting the motor vehicle is generally attained solely by an intentional change or activation/control of the torque transmittable by the clutch.
It is also advantageous if the larger available engine torque is the maximum engine torque.
It is furthermore advantageous if the control unit initiates shifting between operating states only when a sensor indicates that a load lever, such as the gas pedal, is operated in a way that a predetermined threshold value of the load lever value has or has not been reached or exceeded.
It is especially advantageous if the control unit, when determining an insufficient or excessive acceleration of the motor vehicle based on data sets, such as signals, quantities, sensor signals or other operating parameters which are accumulated, detected and/or processed, initiates shifting between two operating states.
It is advantageous if the apparatus according to the invention if the control unit compares at least one data set with at least one presentable threshold value for detecting an insufficient or excessive acceleration when at least one data set has at least reached, exceeded or is below one threshold value.
It is also advantageous if the control unit determines an insufficient or excessive acceleration and initiates shifting between two operating states, when at least one data set which is detected or determined as a function of time, reaches, does not reach, exceeds or drops below a presentable threshold value after a preset time period.
In addition, it is advantageous if the control unit determines an excessively weak acceleration and initiates shifting between two operating states, when during a first acceleration phase or starting phase of the vehicle a quantity representing the transmission input RPM has not increased above a presentable threshold value after a preset time period.
In an apparatus of the invention, it may be advantageous if the control unit initiates shifting from an operating state with a smaller transmittable torque of the torque transmitting system and a smaller available engine torque to a state with a larger transmittable torque of the torque transmitting system and a larger available engine torque in such a way that, during a first phase, there is initiated an at least small decrease of the transmittable torque of the torque transmitting system and that, in a second phase, the transmittable torque of the torque transmitting system is increased to a larger target value.
It may also be advantageous if the control unit initiates shifting from an operating state with a larger transmittable torque of the torque transmitting system and a larger available engine torque to a state with a smaller transmittable torque of the torque transmitting system and a smaller available engine torque in such a way that, during a first phase, there is selected an increase of the transmittable torque of the torque transmitting system and that, during a second phase, the transmittable torque of the torque transmitting system is decreased to a smaller target value.
It may also be advantageous if the transmittable torque selected by the control unit Mkset of the torque transmitting system is a function f of the engine RPM nmot:
Mkset=k*f(nmot).
It may be particularly advantageous if during a controlled shifting operation from one operating state into another operating state, the control unit determines the transmittable torque of the torque transmitting system according to Mkset=k*f(nmot), wherein the control unit selects the value of k from a range of values between 0 and a maximum value kmax and changes, such as increases or decreases, the value of k during a shifting operation.
Furthermore, it is advantageous if during a intentional controlled shifting operation from a first operating state into a second operating state with a higher transmittable torque and a higher available engine torque, the control unit controls the driving torque acting on the drive in such a way that the torque which results from the transmittable engine torque at the output end, is increased.
A method of the invention for controlling a torque transmitting system in the power train of a vehicle with a transmission, a torque transmitting system and an engine, with an apparatus for controlling a torque transmitting system, with at least one actuator controllable by a control unit, such as an actuating unit, for operating the torque transmitting system, wherein the control unit is in signal communication with sensors and possibly with other electronic units, may advantageously be characterized in that the control unit executes or controls at least the following method steps:
a) recognizing an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal,
b) recognizing the actual load lever value and comparing the load lever value with a threshold value and evaluating if the load lever value exceeds the threshold value
c) recognizing an excessively low acceleration based on at least one data set, such as a sensor signal,
d) controlling the torque transmitting system for switching from a state with a smaller transmittable torque and smaller available engine torque into a state with a larger transmittable torque of the torque transmitting system and larger available engine torque such that during a first phase there is initiated a reduction of the transmittable torque and during a second phase, the transmittable torque is increased to a higher target value.
Further, a method according to the invention for controlling a torque transmitting system in the power train of a vehicle with a transmission, a torque transmitting system and an engine, with an apparatus for controlling a torque transmitting system, with at least one actuator controllable by a control unit, such as an actuating unit, for operating the torque transmitting system, wherein the control unit is in signal communication with sensors and possibly with other electronic units, may also be preferably characterized in that the control unit executes, such as controls or regulates, at least the following process steps: recognizing an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal, recognizing the actual load lever value and comparing the load lever value with a threshold value and evaluating if the load lever value exceeds the threshold value, recognizing an excessively high acceleration based on at least one data set, such as a sensor signal, controlling the torque transmitting system for switching from a state with a larger transmittable torque and larger available engine torque into a state with a smaller transmittable torque of the torque transmitting system and smaller available engine torque such that during a first phase there is brought about an increase of the transmittable torque and during a second phase, the transmittable torque is decreased to a lower target value.
It is advantageous if the control unit recognizes an operating state, such as a starting or acceleration state, based on at least one data set, such as a sensor signal, wherein a starting or acceleration state can be detected by way of at least one activated load lever, inactive brakes or a gear engaged in the transmission.
Also, it is advantageous if the control unit determines or processes at least one quantity or a data set as a function of time and at least in general compares said at least one quantity to a presentable threshold value, wherein said quantity is a measure for the speed or acceleration of the vehicle.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.